[Anticline]—an arch-like fold in the [rocks], with the beds dipping in opposite directions on the two sides.
[Aquifer]—a water-bearing layer of porous and permeable [rock].
[Aragonite]—a form of calcium carbonate (CaCO₃).
[Archeozoic]—the oldest known geological [era]; early Precambrian.
[Bedding plane]—the plane of demarcation between two individual [rock] layers or [strata].
[Calcite]—a [mineral] composed of calcium carbonate, CaCO₃.
[Caliche]—an accumulation of calcium carbonate, commonly white in color, in the soil profile.
[Cenozoic]—the latest [era] of geologic time, containing the Tertiary and Quaternary [Periods] and continuing to the present time.
[Chert]—dense, hard [rock] of very fine-grained [silica], usually in nodular form. This material is also called flint.
[Concretion]—a concentration, usually spherical, of [mineral] matter in [sedimentary] [rocks], produced by deposits from solution; it is harder than the surrounding rock.